syzbot


INFO: task hung in do_renameat2 (4)

Status: upstream: reported on 2026/02/11 16:33
Reported-by: syzbot+e6abc33728184c9172d7@syzkaller.appspotmail.com
First crash: 48d, last: 8d12h
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in do_renameat2 (2) ext4 1 C inconclusive error 278 88d 695d 0/29 upstream: reported C repro on 2024/05/06 01:51
linux-6.1 INFO: task hung in do_renameat2 (3) 1 1 184d 184d 0/3 auto-obsoleted due to no activity on 2026/01/07 13:07
linux-5.15 INFO: task hung in do_renameat2 origin:lts-only 1 C done 6 449d 687d 0/3 auto-obsoleted due to no activity on 2025/04/16 19:25
linux-6.1 INFO: task hung in do_renameat2 1 1 792d 792d 0/3 auto-obsoleted due to no activity on 2024/05/09 03:01
upstream INFO: task hung in do_renameat2 f2fs 1 2 938d 973d 0/29 auto-obsoleted due to no activity on 2023/12/04 15:30
linux-6.1 INFO: task hung in do_renameat2 (2) 1 1 686d 686d 0/3 auto-obsoleted due to no activity on 2024/08/22 17:29

Sample crash report:
INFO: task syz.0.3358:14270 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.3358      state:D stack:29168 pid:14270 ppid:13600  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 rwsem_down_write_slowpath+0xc2e/0x1110 kernel/locking/rwsem.c:1189
 lock_rename include/linux/fs.h:-1 [inline]
 do_renameat2+0x435/0xce0 fs/namei.c:4974
 __do_sys_rename fs/namei.c:5081 [inline]
 __se_sys_rename fs/namei.c:5079 [inline]
 __x64_sys_rename+0x82/0x90 fs/namei.c:5079
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2b0099c799
RSP: 002b:00007f2b018a0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007f2b00c16090 RCX: 00007f2b0099c799
RDX: 0000000000000000 RSI: 00002000000009c0 RDI: 0000200000000a00
RBP: 00007f2b00a32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2b00c16128 R14: 00007f2b00c16090 R15: 00007fffea7b5b28
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2dfb0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2e7d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4025:
 #0: ffff88802f69f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198
3 locks held by kworker/u4:5/4294:
 #0: ffff8880b8e3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:538
 #1: ffff8880b8f27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999
 #2: ffffffff96cca788 (&fsnotify_mark_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #2: ffffffff96cca788 (&fsnotify_mark_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline]
 #2: ffffffff96cca788 (&fsnotify_mark_srcu){....}-{0:0}, at: srcu_gp_start_if_needed+0x175/0xff0 kernel/rcu/srcutree.c:1094
2 locks held by kworker/u4:7/4524:
1 lock held by udevd/4640:
 #0: ffff8880b8f3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:538
2 locks held by kworker/0:12/5851:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000c2dfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/0:16/5857:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000c35fd00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #2: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
2 locks held by syz-executor/11187:
 #0: ffff88806503a0e0 (&type->s_umount_key#61){++++}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362
 #1: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #1: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
4 locks held by syz.0.3358/14247:
2 locks held by syz.0.3358/14270:
 #0: ffff888073760460 (sb_writers#18){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
 #1: ffff8880700b8f30 (&sb->s_type->i_mutex_key#22/1){+.+.}-{3:3}, at: lock_rename include/linux/fs.h:-1 [inline]
 #1: ffff8880700b8f30 (&sb->s_type->i_mutex_key#22/1){+.+.}-{3:3}, at: do_renameat2+0x435/0xce0 fs/namei.c:4974
1 lock held by syz-executor/14580:
 #0: ffff88807a6820e0 (&type->s_umount_key#109){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362
1 lock held by rm/17448:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4524 Comm: kworker/u4:7 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:212
Code: 2e 0f 1f 84 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d f0 66 9d 0c 48 89 de 5b e9 77 21 50 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d 84 fc 7f 7e 65 8b 15 85 fc 7f 7e 81 e2 00
RSP: 0018:ffffc90004fa7b68 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff89f6a330 RCX: ca5f2dfb2eb72700
RDX: ffff88807c925940 RSI: ffffffff8adf0f40 RDI: ffffffff8adf0f00
RBP: ffff88807cb33830 R08: dffffc0000000000 R09: 1ffffffff215ec48
R10: dffffc0000000000 R11: fffffbfff215ec49 R12: dffffc0000000000
R13: 1ffff1100a7c7af3 R14: 0000000000000001 R15: ffff888053e3cc80
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6c3f55fe9c CR3: 0000000030788000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_read_lock include/linux/rcupdate.h:792 [inline]
 batadv_nc_process_nc_paths+0x103/0x390 net/batman-adv/network-coding.c:687
 batadv_nc_worker+0x425/0x600 net/batman-adv/network-coding.c:728
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/24 01:49 linux-6.1.y f2ddafa93a25 baf8bf12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in do_renameat2
2026/02/11 16:32 linux-6.1.y 8ce36b2849ef 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in do_renameat2
* Struck through repros no longer work on HEAD.